Question

My friend found two old watches. He wound them, set them, and started both of them at the same time. He placed the two old watches on one wrist and his new watch on the other wrist. Forty-five minutes later one of the old watches had gained 1 minuate and the other old watch lost 2 minutes. The next morning one watch read 7:00 and the other read 6:00. At what time did he start the two old watches?

I need a good explanation on how to solve this problem. Thanks